Parliamentary Under Secretary of State for Defence Peter Luff told Dr Lucas: “The cost incurred by the Ministry of Defence as a result of the flood at the Atomic Weapons Establishment (AWE) in 2007 was some £5 million. The Ministry of Defence Police based at Burghfield also incurred flood-related costs totalling £110,000 which did not form part of the AWE Management Ltd claim.

“A small claim from an AWE sub-contractor has still to be resolved.

“The £5 million flood-related costs described above were incurred by AWE Management Ltd and their operating company, AWE plc, and were the costs claimed from the department under non-nuclear indemnity. No costs were incurred by commercial insurers as a result of the flood, as the non-nuclear indemnity is in place to cover such events.”

Director of the Nuclear Information Service Peter Burt said: “The scale of flooding at Burghfield in 2007 was entirely the result of failings by AWE plc, who had neglected a programme of remediation works and overlooked flood risks in emergency plans, even though the company knew the site had a history of flooding.

“Over in the USA President Obama has forced multinational oil company BP to pay for the mistakes it has made over the Gulf of Mexico oil spill, but here in the UK the Ministry of Defence is quite happy to hand taxes paid by hard working families over to AWE – a consortium of some of the richest military contractors in the world – so that the company doesn’t lose money over the damage caused during the floods.

“AWE should be ashamed of the way it has conducted itself over this scandalous affair and should repay the money to the Treasury at once.”

AWE: ‘July rain unusual event’

The spokeswoman for AWE, Rachel Whybrow, said: “An indemnity exists in the contract for certain non-nuclear risks which, at that time, could not be covered under commercial insurance terms, the costs being either prohibitive or unavailable.

“The claim for property damage (and associated labour costs) related to the flood was such a risk.

“The July 2007 rainfall was very unusual and extreme (it was assessed as a one-in-215-year event), and many facilities throughout the country struggled to cope with resultant flooding of this magnitude.

“The review of the extent of the flooding was subject to our regulatory regime and wide public exposure, with all appropriate controls having been met.

“At no time during the flooding or during the programme of remedial works was nuclear safety compromised on AWE sites.

“AWE operates a process of continuous improvement and, as a matter of course, conducted a comprehensive review following the 2007 floods. Its recommendations continue to be implemented.”